JP6483006B2 - Wind farm and its control method - Google Patents

Description

  The present invention relates to a wind farm and a control method thereof, and more particularly, to a wind farm and a control method thereof capable of providing benefits to an electric power system.

Long time so the depletion of petroleum fossil fuel is concerned, also for warming the global environment, reducing emissions of CO ₂ has become an issue of urgent to be solved worldwide. In order to solve these problems, renewable energy power generation using natural energy, such as solar power generation and wind power generation, has been introduced around the world as a power generation method that does not use fossil fuels and does not emit CO _2. Is progressing rapidly.

  However, wind power generation, in particular, is characterized by the fact that the generated power fluctuates greatly over time because it generates power using wind that changes from moment to moment. For this reason, when the generated power is linked to the power grid, fluctuations in wind power generation can cause unbalanced power supply and demand in commercial power grids, causing problems such as voltage fluctuations and frequency fluctuations. It is feared that this will lead to a decline.

  Currently, when wind power generation is linked to the power grid, the power output from the large power generators such as thermal power stations in the power grid is adjusted according to the power demand on the power grid side. The balance between supply and demand is maintained. However, in Japan, many wind power generation companies have already linked the wind power generation system to the grid, and the number of such companies is also on the rise. ing.

  In view of this, a method has been proposed in which a wind power generator group (wind farm) including one or more wind power generators is used to suppress voltage fluctuations in the power system using reactive power output from the wind power generator. For example, in Patent Document 1, “a parameter α (t) that changes from time to time based on each detected value of the fluctuation component ΔP of the active power P output from the distributed power source 1 itself and the voltage fluctuation ΔV of the cooperation point X5 generated thereby. The distributed power source 1 outputs reactive power Q = −αP or Q = −αΔP and suppresses only the voltage fluctuation of the system 3 caused by the distributed power source 1 ”. Yes.

  In addition, as a technique for suppressing frequency fluctuations in the power system, a wind farm in which some wind power generators of the wind farm are restricted to output as a wind power generator group for adjustment and there is a concern about frequency fluctuations in the power system. There has been proposed a method of suppressing the frequency fluctuation of the power system by releasing the output restriction of the adjusting wind power generator when the output suddenly changes. For example, in Patent Document 2, “a control system for a group of wind power generators configured to include a plurality of wind power generation systems connected to an electric power system via power transmission lines and at least one power storage system. An individual control device that is provided in each of the plurality of wind power generation systems and the power storage system and transmits and receives operation information including the output of each of the plurality of wind power generation systems via a communication network, and via the communication network A centralized control device that receives information from the individual control device and computes output limit values of the plurality of wind power generation systems, and the plurality of wind power generation systems from the centralized control device. The operation of the wind turbine generator group is controlled in accordance with the output command value transmitted to each of the above.

JP 2007-1224779 A JP 2012-241576 A

  According to Patent Documents 1 and 2, a large-capacity wind farm can contribute to stable operation of power system voltage and frequency. However, depending on the capacity and impedance of the power system with which the wind farm is linked, the wind power generator group may be used when the effect of suppressing the voltage fluctuation by the reactive power output is small or when the power system has sufficient reserve capacity. There may be a case where it is not necessary to suppress frequency fluctuations by limiting or releasing the output.

  On the other hand, when a large amount of renewable energy power generation such as wind power generation or solar power generation is introduced into the power system, system support capability (including ancillary service to the power system) including voltage fluctuation suppression and frequency fluctuation suppression at the wind farm level It is thought that control that brings the most benefit to the power system will be required. When such an ancillary service is performed, there is a concern that the conventional technology may not provide the most beneficial control.

  In view of the above-described problems of the prior art, the object of the present invention is to provide the most benefit to the power system by appropriately controlling the active power and reactive power of the wind farm wind power generator. It is to provide a wind farm having a wind power generation control device and a control method therefor.

  In order to solve the above-described problem, in the present invention, a wind farm that adjusts power supplied from a wind turbine generator to a power system via a power converter by a control device, the control device includes active power in the power system. Or from the power value estimator that obtains information on the value of reactive power, the information on the value of active power or reactive power obtained by the power value estimator, and the information on loss from the converter to the link point of the power system A control effect comparison unit that calculates a control effect, and a control that externally presents or transmits active power or reactive power as a control plan when maximizing the control effect obtained by the control effect comparison unit for a plurality of operating conditions in the power system A plan determining unit is provided.

  Further, in the present invention, a wind farm in which a plurality of sets of outputs of a wind power generation system including a wind power generation device and a power converter are connected in parallel and connected to an electric power system at a cooperation point, and the control device is an electric power system A power value estimator that obtains information on the value of active power or reactive power from the sensitivity of frequency to active power or the sensitivity of voltage to reactive power and the required amount of frequency or voltage tolerance, and power value estimation The control effect determined by the information on the value of active power or reactive power obtained in the department and the loss information from the converter to the power system linkage point in multiple sets of wind power generation systems is attached to multiple operating conditions. The control effect comparison unit to find and compare, and the active power or reactive power at the time of the operating condition that maximizes the control effect is presented externally as a control plan, or Characterized in that it comprises a control plan determining unit signal to.

  Further, in the present invention, there is provided a wind farm control method for adjusting power supplied from a wind turbine generator to a power system via a power converter by a control device, the frequency sensitivity with respect to active power in the power system or reactive power Obtain information on the value of active power or reactive power from information such as the sensitivity of voltage and the required amount of frequency or voltage tolerance, and link the power system from the converter with information on the value of active power or reactive power The control effect determined by the loss information up to the point is obtained for multiple operating conditions, and the active or reactive power at the operating condition that maximizes the control effect is externally presented or transmitted as a control plan. It is characterized by.

  According to the present invention, it is possible to provide a system that can optimally control the active power and reactive power of a wind farm and can stably operate the power system.

The figure which shows the structure of the wind farm and electric power system in Example 1 of this invention. The functional block diagram of the wind farm control apparatus in Example 1 of this invention. The figure which showed an example of the value information of the active power in Example 1 of this invention. The figure which showed an example of the value information of the reactive power in Example 1 of this invention. The figure which showed the reflection method to the kind of ancillary service with respect to the electric power grid | system in Example 1 of this invention, and a wind farm control plan. The figure which showed an example of the output possible range of active power and force reactive power of a power converter. The figure which showed the example of a structure of the several wind power generation system and the current collection cable from each wind power generation system to the cooperation point X of an electric power grid | system. The figure which showed an example of the time-sequential change of active power and reactive power which are output to a power grid from a wind farm. The figure which showed an example of the time-sequential change of active power and reactive power which are output to a power grid | system from a wind farm when the value of driving reserve and reactive power is high. The figure which shows the example which compared the income of the electric power generation company of a wind farm. The figure which shows the structure of the wind farm and electric power system in Example 2 of this invention. The functional block diagram of the wind farm control apparatus in Example 2 of this invention. The figure which showed an example of the method of outputting active power actively from the wind farm in Example 2 of this invention. The figure which showed an example of the method of outputting reactive power actively from the wind farm in Example 2. FIG. FIG. 10 is a diagram illustrating an example of a method for estimating the sensitivity of active power in the second embodiment. FIG. 10 is a diagram illustrating an example of a method for estimating the reactive power sensitivity according to the second embodiment. The flowchart which shows a series of processes by the wind power generation control method which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a wind farm and a power system in Embodiment 1 of the present invention.

  According to the configuration of FIG. 1, electric power is supplied to the electric power system 5 from the wind farm 100 that is a renewable energy power plant, and the electric power company 8 takes in the measurement signal from the electric power system 5 and is owned by the electric power company 8. The other power generation equipment in 5 or the power transmission equipment is controlled by an appropriate control signal so as to operate optimally.

  In the present configuration, the power company 8 is positioned as a power transmission company and the wind farm 100 is positioned as a power generation company in the near future after the separation of dispatched power. The relationship of the wind farm 100 (power generation company) supplying power to the power system does not change at all.

  From the viewpoint of one wind farm 100 (power generation company), it is advantageous that both companies can supply power to the power system 5 as much as possible, and from the other power company 8 (power transmission company). In order to achieve stable operation, there are scenes that require the cooperation of the wind farm 100 (power generation company). Not only the maximum power generation according to the wind conditions, but also cooperation such as limiting or stopping as necessary is required. For this reason, it is desired that the system be operated with satisfactory content.

  The wind farm 100 in FIG. 1 creates a control plan CP of the wind farm 100 with contents suitable for the operation of the electric power system 5 in the electric power company 8 (transmission company) and presents it to the electric power company 8 (transmission company). To do. Further, the power (active power P, reactive power Q) generated in the wind farm 100 is controlled in accordance with the created control plan CP. In this case, the control plan CP is preferably obtained only from the measurement information that can be grasped on the wind farm 100 side. In general, since the wind farm 100 and the electric power company 8 (transmission company) are different companies, it is assumed that it is difficult to obtain information from the electric power company 8 (transmission company) and make a control plan. It is preferable that the control plan is based on information on the wind farm 100 side.

  A wind farm 100 in FIG. 1 includes a wind power generation system 1 and a control device 3. Of these, the wind power generation system 1 is composed of one or a plurality of wind power generation devices GW and a power converter C that converts the generated power of the wind power generation device GW into power having a form and size suitable for the power system 5. ing. The wind turbine generator GW is a wind turbine generator that can be controlled with a variable rotation speed and pitch. The power converter C is a power converter that can independently control the active power P and the reactive power Q that flow through the power system 5 from the generated power of the wind power generator GW.

  The electric power company 8 operates the electric power system 5 and is responsible for maintaining a balance between power demand and supply in the electric power system 5 and voltage within an appropriate range. The responsibility division point of the electric power company 8 (power transmission company) and the wind farm 100 (power generation company) is the linkage point X, and the power (active power P, reactive power Q) at the point X is controlled by the control device 3, The voltage V and the frequency f at the point X are to be measured and controlled.

  The control device 3 in the wind farm 100 presents the control plan CP of the wind farm 100 to the electric power company 8 (transmission company), and the power command values (active power command value Pd, reactive power command value Qd) according to the control plan CP. Is supplied to the wind power generator GW for operation control. In order to create these control plans CP and create power command values (active power command value Pd, reactive power command value Qd), the control device 3 inputs the output M of the wind power generator GW, or receives sensitivity information, necessary Necessary information is held in advance in the quantity information database DB1, cable characteristics, converter characteristics database DB2, and ancillary service information database DB3.

  The information stored and stored in the sensitivity information and necessary amount information database DB1 is information on the sensitivity and necessary amount of active power or reactive power exemplified in FIGS. The information stored and stored in the cable characteristics and converter characteristics database DB2 includes the characteristics such as the impedance of the cable connecting the wind power generation system 1 in the wind farm 100 illustrated in FIG. Information. The information stored and stored in the ancillary service information database DB3 is information on the type of ancillary service illustrated in FIG. In addition, the control device 3 in the wind farm 100 periodically captures various information indicating the operating conditions of the power system.

  FIG. 2 is a functional block diagram of the wind farm control device 3 according to the first embodiment. The control device 3 can be divided into a system sensitivity analysis unit 31 and a control plan determination unit 32 when the functions are roughly classified.

  Among these, the system sensitivity analysis unit 31 reads the sensitivity information, the active power, the reactive power sensitivity, and the necessary amount held in the necessary amount information database DB1, and stabilizes the voltage, frequency, stability, etc. of each power system. An estimation unit (active power value estimation unit 311, reactive power value estimation unit 312) that estimates the active power value Wp and reactive power value Wq for the operation, and the cable characteristics in the wind farm 100 are read to calculate the cable loss. Cable loss calculation unit 313.

  Note that the estimation units (the active power value estimation unit 311 and the reactive power value estimation unit 312) are sensitive information in estimating the active power value Wp and the reactive power value Wq for stable operation such as the voltage, frequency, and stability of the power system. The active power value Wp and the reactive power value Wq are estimated and output with reference to the necessary amount information database DB1.

  FIG. 3 is a diagram showing an example of the sensitivity of the active power P held in the sensitivity information / necessary amount information database DB1. The horizontal axis indicates the effective power change amount ΔP, and the vertical axis indicates the suppression amount of the frequency change amount Δf. The active power P output from the wind farm 100 to the power system 5 via the linkage point X is It represents the sensitivity (Δf / ΔP) of how much the frequency f changes.

  FIG. 4 is a diagram showing an example of the sensitivity of the reactive power Q held in the sensitivity information / necessary amount information database DB1. The horizontal axis indicates the reactive power change amount ΔQ, and the vertical axis indicates the suppression amount of the voltage change amount ΔV. The reactive power Q output from the wind farm 100 to the power system 5 via the linkage point X is It represents the sensitivity (ΔV / ΔQ) of how much the voltage V changes.

  In these examples, the active power sensitivity (Δf / ΔP) is the amount of suppression of the frequency fluctuation Δf of the power system, and indicates that the amount of suppression of Δf increases as the amount of change ΔP in active power increases. . The reactive power sensitivity (ΔV / ΔQ) is the amount of suppression of voltage fluctuation ΔV of the power system, and indicates that the amount of suppression of ΔV increases as the amount of change ΔQ in reactive power increases. Sensitivity (Δf / ΔP) and (ΔV / ΔQ) information varies depending on the power system configuration, power flow conditions, etc., and the sensitivity information is created by the power company (transmission company) or operates a wind farm. The person may create the information based on information on the power system. Further, these pieces of sensitivity information change from moment to moment according to the state of the power system.

  When the power generation company that operates the wind farm 100 generates these sensitivities (Δf / ΔP) and (ΔV / ΔQ), the sensitivity information and the necessary amount information database DB1 are obtained in advance from the past operation results at the linkage point X. Or is appropriately determined from the current driving performance and used.

  Sensitivity information and the necessary amount information in the necessary amount information database DB1 mean operating restriction conditions. Regarding the control of the active power P, it is information on limiting conditions such as a fluctuation allowable range, an upper limit value, a lower limit value, etc., for the frequency f of the power system that fluctuates as a result of controlling the active power P. Usually, it is in the range of 0.2 to 0.3 Hz with respect to the commercial frequency. In terms of controlling the reactive power Q, it is information on limiting conditions such as a fluctuation allowable range, an upper limit value, and a lower limit value of the voltage V of the power system that fluctuates as a result of controlling the reactive power Q. The necessary amount information is determined by the electric power company 8 or a power transmission company (not shown) based on the power flow state of the power system.

  The active power value estimation unit 311 and the reactive power value estimation unit 312 in the system sensitivity analysis unit 31 mean sensitivity information, active power held in the necessary amount information database DB1, sensitivity of reactive power, and operation restriction conditions. The necessary amount of information is read, and the active power value Wp and reactive power value Wq for stable operation such as voltage, frequency, and stability of each power system are estimated.

  For example, the active power value estimation unit 311 of the system sensitivity analysis unit 31 indicates how much the frequency f of the power system changes with respect to the active power P output from the wind farm to the power system 5 via the linkage point X. Sensitivity information and the necessary amount such as the allowable range of fluctuation of frequency f, the upper limit value, the lower limit value, etc. determined by the electric power company 8 and the power transmission company (not shown) based on the power flow state of the power system From the information, the value of active power is estimated. Specifically, when the power system 5 to which the wind farm is linked is far from the substation, when the sensitivity of the frequency f is high and the fluctuation allowable range of the frequency f is narrow, the effective power P of the wind farm is It is estimated that the value Wp of the active power is high because the change in power has a great influence on the power system.

  Similarly, the reactive power value estimation unit 312 includes sensitivity information indicating how much the voltage V of the power grid 5 changes with respect to the reactive power Q output from the wind farm to the power grid 5 via the linkage point X. The value of reactive power from the information on necessary amounts such as the allowable range of fluctuation of voltage V, the upper limit value, the lower limit value, etc., determined by the electric power company 8 and the power transmission company based on the power flow state of the power system, etc. Estimate Wq.

  The reason for considering the necessary amount information in the active power value estimation unit 311 and the reactive power value estimation unit 312 is as follows. In situations where active power control or frequency control is desired, the frequency changeable range is determined based on the relationship between the current frequency and its allowable fluctuation range, and the active power or frequency is unlimited when considering the sensitivity (Δf / ΔP). It is not changeable and will have a finite change range. This also applies to the relationship between reactive power and voltage. In situations where reactive power control or voltage control is desired, the voltage changeable range is determined from the relationship between the current voltage and its allowable fluctuation range, and the reactive power or voltage is unlimited when considering the sensitivity (ΔV / ΔQ). It is not changeable and will have a finite change range. For this reason, since the active power value Wp or the reactive power value Wq varies depending on the range of changeable range, it is better to consider in view of necessary amount information.

  Further, the cable loss calculation unit 313 in the system sensitivity analysis unit 31 reads the cable characteristics stored in the cable characteristic / converter characteristic database DB2 and calculates the cable loss. Although details of the cable loss calculation unit 313 will be described later, in short, as cable characteristics, information on impedance in the cable from the power converter C to the linkage point X is held, and the power loss in this portion is obtained. The power loss Lc is not always a constant value, but is a function of active power and reactive power determined by the operating conditions of the power converter C, and is a variable value Lc. In addition, since the wind power generation system 1 including the wind power generation device GW and the power converter C is connected in parallel in the wind farm 100 as shown in FIG. Lc includes the individual cable loss in each wind power generation system 1 and the sum thereof.

  In this manner, the system sensitivity analysis unit 31 gives the active power value Wp, the reactive power value Wq, and the cable loss Lc as analysis results. In the present invention, the analysis result from the system sensitivity analysis unit 31 is given as a plurality of analysis results from the viewpoint of an ancillary service with reference to the ancillary service information database DB3 instead of the one set described above.

  Here, the ancillary service is a system support capability including voltage fluctuation suppression and frequency fluctuation suppression at the wind farm level. When a large amount of renewable energy power generation such as wind power generation or solar power generation is introduced into the power system 5, the wind farm 100 is required to control the power system 5 so as to provide the most benefit. As a result, the power generation company on the wind farm side does not determine the power generation output due to its own circumstances, but intends to operate with great merit for the power transmission company side.

  FIG. 5 is a diagram showing the types of ancillary services for the electric power system and the reflection method to the wind farm control plan for realizing each service by the wind farm. The type of ancillary service means the operating conditions of the ancillary service. Ancillary services required for stable operation of the power system include No1 (frequency control), No2 (imbalance adjustment), No3 (instantaneous reserve capacity), No4 (operation reserve capacity), No5 (system control, scheduling, power supply) Command), No. 6 (reactive power supply and voltage control), No. 7 (backup supply), etc., each of which can be dealt with by controlling the active power P and reactive power Q of the wind farm 100.

  For example, in the frequency control of No. 1, when the frequency of the power system 5 increases due to a sudden decrease in load or the like, the effect of reducing the frequency of the power system 5 is obtained by suppressing the active power of the wind farm 100. On the other hand, when the frequency of the power system 5 decreases due to a sudden increase in load or the like, the effect of increasing the frequency of the power system can be obtained by releasing the suppression of the active power of the wind farm 100.

  Further, regarding the reactive power supply and voltage control of No. 6, when the voltage of the power system 5 decreases, an effect of increasing the voltage of the power system 5 can be obtained by proceeding from the wind farm 100 and supplying reactive power. Conversely, when the voltage of the power system 5 rises, the effect of lowering the voltage of the power system 5 can be obtained by supplying delayed reactive power from the wind farm 100. The active power and reactive power are controlled by the power converter C.

  Note that each ancillary service from No. 2 to No. 5 and No. 7 can be similarly realized by suppressing the active power P of the wind farm and suppressing release control. Here, the reflection method is only illustrated in FIG. 5, and the detailed description is omitted.

  As a result, the active power value estimation unit 311 and the reactive power value estimation unit 312 in the system sensitivity analysis unit 31 give the values of the active power value Wp and the reactive power value Wq multiplied by the number of service items of the ancillary service. Will be.

  The control plan determination unit 32 includes the analysis result of the system sensitivity analysis unit 31 (the active power value Wp, the reactive power value Wq, and the power loss Lc), the cable characteristics, and the power converter C stored in the converter characteristics database DB2. Read unit price information of characteristics, active power, reactive power, control effect comparison unit 321 for comparing control effects, and based on the comparison result of control effects, determine control plans CPP, CPQ of active power and reactive power, And a control plan determination unit 322 for presenting the result.

  More specifically, in the control effect comparison unit 321 of the system sensitivity analysis unit 31 in FIG. 2, the active power value Wp and the reactive power value Wq obtained by the system sensitivity analysis unit 31 for each ancillary service are collected in the wind farm. What combination of active power P and reactive power Q is obtained from information such as the loss Lc of the electric cable, unit price information Up and Uq of active power and reactive power, and characteristics of the power converter of the wind power generation system 1. It is compared whether the control effect is the highest and the income of the power generation company of the wind farm 100 is increased.

  Here, assuming that the value of the quantified active power is Wp, the value of the reactive power is Wq, the unit price of the active power is Up, the unit price of the reactive power is Uq, and the loss of the cable is Lc, the control effect index E is, for example, (1 ).

  In the present invention, in order to maximize the control effect index E, the control effect in ancillary service or power factor constant control is compared as the operating condition to be applied, and the active power and invalidity at the selected control effect are compared. Determine the power control plan.

  FIG. 6 is a diagram illustrating an example of a possible output range of the active power P and the reactive power Q of the power converter C, which is a component of the wind power generation system 1. In the region indicated by the active power P on the horizontal axis and the reactive power Q on the vertical axis, the output possible range is limited to a range where the reactive power is ± 0.4 (pu). In the region where the active power is small, the reactive power is limited to a small range.

  The power converter C has a function of adjusting the voltage V and the frequency f in order to flow the generated power of the wind power generator GW to the power system 5. At this time, by controlling the phase of the output voltage and the output current, it is possible to control by the ratio of the active power P and the reactive power Q in the range shown in the figure. Normally, the power converter C is operated with a power factor of 1.0 (reactive power of 0 Var) or a constant power factor (P / Q = constant), but in the present invention, the type and combination of ancillary services to be applied Accordingly, the ratio between the active power P and the reactive power Q is changed in the region.

  Note that the sensitivity information in FIG. 1 and the information on the necessary amount stored and stored in the necessary amount information database DB1 are the power system frequency and voltage limiting conditions (allowable fluctuation range). The output possible range of the active power P and the reactive power Q of the power converter C is also a limiting condition (allowable fluctuation range) when the wind farm 100 is operated. Therefore, in determining the active power value Wp and the reactive power value Wq, it is preferable to consider the possible output ranges of the active power P and the reactive power Q of the power converter C.

  FIG. 7 shows an example of a configuration of a plurality of wind power generation systems (11 to 1n) in the wind farm 100 and a current collecting cable (41 to 4n) from each wind power generation system to the linkage point X of the power system 5. FIG.

  Each wind power generation system (11 to 1n) outputs active power P (P41 to P4n) and reactive power Q (Q41 to Q4n), and the voltage at the wind power generation system end is V41 to V4n. To do. At this time, if the impedance of the current collecting cable (41 to 4n) from the wind power generation system (11 to 1n) to the linkage point X is represented by Z41 to Z4n, respectively, the transmission loss Lc in the wind farm 100 is (2). It is expressed by a formula.

  In equation (2), the subscript n represents the number of wind power generation systems in the wind farm. In addition, the effective powers P41 to P4n are determined by the wind energy, and are determined according to the wind energy received by each wind power generation system even when the effective power is suppressed or controlled to be canceled.

  According to the equation (2), when the reactive power Q is output from the wind farm 100 by the ancillary service, it can be understood that the transmission loss LOSS can be changed by changing the distribution of the reactive power Q41 to Q4n.

  Further, in order to minimize the expression (2) (and hence maximize the output), the ratio of the reactive power Q41 to Q4n may be determined as the expression (3). That is, the reactive power distribution is made to be the ratio of the reciprocal of the impedance of the current collecting cable, so that the reactive power Q of the cable with high impedance is reduced, and the reactive power Q of the cable with low impedance is distributed high, so that The reactive power loss can be minimized.

  At the same time, the reactive power only needs to be Q in total, so it is only necessary to satisfy equation (4).

  By controlling the active power P and reactive power Q of the wind power generation system 1 in the wind farm 100 in this way, the active power and reactive power corresponding to each ancillary service are output from the linkage point X, and the wind farm Control that minimizes power transmission loss is possible.

  FIG. 8 is a diagram illustrating an example of a time-series change of the active power P and the reactive power Q output from the wind farm 100 to the power system 5. This example is a case where the value Wp of the active power P such as reserve power is small, the value Wq of the reactive power Q is small, or the power factor (1.0) is the maximum value. It is convenient for the power generation company to sell all the power generated by the wind farm at a fixed purchase price FIT (Feed-in Tariff Program) without providing services. In such a case, the active power P changes according to the wind speed that changes from time to time, and the reactive power is always zero.

  FIG. 9 shows an example of a time series change of the active power P and the reactive power Q when the value Wq of the operation reserve power and the reactive power Q is high and the optimal control changes with time. It is a figure. In the period from time T0 to T1, it is assumed that the value Wp of the active power P of the operating reserve is high, and the active power is used to secure a part of the active power P that can be generated by the wind farm 100 as the operating reserve. P is controlled and controlled. In this way, in the situation where the operating reserve is emphasized, the wind power plant does not output the changing wind force, but prioritizes the situation on the power transmission company side to suppress the active power P to a constant value.

  Assuming that the value Wq of the reactive power Q is high during the period from the time T1 to the time T2, the maximum reactive power that can be output within the operable range of the power converter C as shown in FIG. Control.

  In the period from time T2 to T3, assuming that the value when combining the operation reserve and reactive power is maximized, if a part of the active power that can be generated by the wind farm is secured as the operation reserve, Control to output reactive power.

  FIG. 10 is more effective when it is controlled by wind farm power generation company revenue, ancillary service operating reserve power control, and reactive power control when the power factor is fixed at 1.0 as shown in FIG. It is a bar graph which shows the example which compared the power generation company income of the wind farm of the value maximization control of this invention based on the value of electric power and reactive power.

  In case A with power factor 1.0 control, all the electric power generated by the wind farm is sold at the FIT fee (fixed purchase price), which becomes the revenue of the operator.

  In the control for securing the operation reserve power in case B, in order to suppress a part of the active power that can be generated, the power sold at the FIT fee is reduced as compared with the power factor 1.0 control. Instead, compensation for the ancillary service that secures reserve capacity is paid by the power company or power transmission company, so the total revenue of the power generation company may increase compared to the case of power factor 1.0 control. .

  In addition, in the case C reactive power control, in addition to the power sold at the FIT fee, a price for an ancillary service that supplies reactive power is paid.

  In the case of value maximization control in Case D, the power factor is controlled by 1.0 so that the sum of FIT power sales revenue, operating reserve income, and reactive power supply revenue is maximized. Compared with ancillary services, it can be expected to meet the demands of the power system and increase the income of power generation companies.

  As described above, according to the present invention, the power generation company side estimates the state of the power system from the information that can be grasped by the power generation company, and presents the control plan CP of active power or reactive power to the power transmission company side. The presented contents are the control plan that seems to be the most valuable in the state of the wind farm, power factor 1.0 fixed control, operation reserve power control or reactive power control that is ancillary service, and active power and reactive power Includes value maximization control. In addition, it includes specific details of the ancillary service.

  The control plan is presented to the power transmission company side, but some subsequent actions on the power transmission company side are assumed. The first response is to accept the proposal of the power generation company as it is. In this case, the power generation company operates the wind power generation system according to the control plan proposed by the power generation company. The second response is to accept a part of the proposal from the power generation company, and in this case, the power generation company operates the wind power generation system according to the modified version of the control plan proposed by the power generation company. The third response is to not accept the proposal of the power generation company. In this case, the power generation company discards the control plan proposed by itself and generates power with the wind condition while minimizing transmission loss, for example. It can be considered.

  As described above, according to the first embodiment of the present invention, on the wind farm side, the value when the operation is executed for a plurality of operation contents of the ancillary service is estimated, and the operation contents to be the maximum value are presented to the power transmission company side. doing. As a result, the wind farm side (power generation company side) can perform an operation that is advantageous to the self and that can bring the most benefit to the power system.

  In the first embodiment, sensitivity information and necessary amount information database 1 is provided, and information on sensitivity and necessary amount of active power or reactive power is held in advance. On the other hand, in the second embodiment, sensitivity information is not provided in the sensitivity information / necessary amount information database 1, and information on active power or reactive power sensitivity is obtained from time to time information from time to time. A second embodiment will be described with reference to FIGS.

  FIG. 11 is a diagram illustrating a configuration of a wind farm and a power system in an embodiment in which information about the value of active power and reactive power is obtained from the output of active power and reactive power from the wind farm and measured values. It is. The difference from FIG. 1 is that the active power, reactive power, voltage, frequency, and the like, which are input from the outside, are measured by the measuring device 9 provided at the linkage point X with the value of active power, reactive power, and necessary amount. This is a point obtained from the measured value.

  FIG. 12 is a functional block diagram of the wind farm control device 3 according to the second embodiment. The difference from FIG. 2 is that the system sensitivity analysis unit 31 estimates active power sensitivity from information such as active power P, reactive power Q, voltage V, and frequency f measured at the linkage point X. And a reactive power sensitivity estimation unit 315 for estimating the sensitivity of the reactive power Q.

  FIG. 13 is a diagram illustrating an example of a method for actively outputting active power from the wind farm 100 when estimating the sensitivity of active power in the second embodiment. Here, in order to measure how sensitive the frequency f of the power system responds according to the output fluctuation of the wind farm, the temporal fluctuation of the active power P and the frequency f is input and monitored.

  In the first measurement stage for sensitivity estimation, the active power P of the wind farm is suppressed to a constant value Pc smaller than the power that can be generated from time T0 to T1 in FIG. 13, and the suppression is released at time T1. To do.

  In the second measurement stage, the change Δf in the frequency of the power system at time T1 is recorded with respect to the change ΔPw in the active power when the suppression is released. Since fluctuations in the frequency of the power system include components unrelated to the output of the wind farm, the same control is performed a plurality of times while changing the condition of ΔPw, and the sensitivity of the active power is statistically estimated. FIG. 13 shows that the same measurement is repeated at times 2 and T3.

  FIG. 14 is a diagram illustrating an example of a method of actively outputting reactive power from a wind farm when estimating reactive power sensitivity in the second embodiment. Here, in order to measure the sensitivity with which the voltage V of the power system responds according to the output fluctuation of the wind farm, the temporal fluctuations of the reactive power Q and the voltage V are input and monitored.

  In the first measurement stage for sensitivity estimation, the reactive power of the wind farm is controlled to 0 (pu) during the period from time T0 to T1 in FIG. 14, and then ΔQw is output as reactive power at time T1.

  In the second measurement stage, the change ΔV in the voltage of the power system at the time when the reactive power ΔQw is output is recorded. Since fluctuations in the voltage of the power system include components irrelevant to the active power and reactive power of the wind farm, the same control is performed multiple times by changing the condition of ΔQw, and the reactive power sensitivity is statistically Is estimated.

  FIG. 15 is a diagram illustrating a method for estimating the active power sensitivity from the measured value of the active power ΔPw output from the wind farm and the frequency change Δf of the power system when the active power sensitivity is estimated in the second embodiment. It is the figure which showed an example. Since the measured values of ΔPw and Δf include frequency disturbance, the estimated sensitivity is obtained from a plurality of data by the least square method or the like.

  FIG. 16 illustrates a method for estimating the reactive power sensitivity from the measured value of the reactive power ΔQw output from the wind farm and the voltage change ΔV of the power system when estimating the reactive power sensitivity in the second embodiment. It is the figure which showed an example. Since the measured values of ΔQw and ΔV include voltage disturbances, the estimated sensitivity is obtained from a plurality of data by the least square method or the like.

  According to the second embodiment, since the sensitivity information (Δf / ΔP) and (ΔV / ΔQ) are obtained from the actual power system state in the latest, the second embodiment is obtained from past measurement results and used as fixed values. Sensitivity information (Δf / ΔP) and (ΔV / ΔQ) reflecting the current state more accurately than the database system 1, and thus the active power value Wp and reactive power value Wq can be obtained.

  In the third embodiment, a wind power generation control method will be described with reference to FIG. FIG. 17 is a flowchart showing a series of processing according to the present invention.

  In the flowchart of FIG. 17, in the first processing step S1, information on active power, reactive power sensitivity, and necessary amount is confirmed. Specifically, in the case of the database system of the first embodiment, the sensitivity information and necessary amount information database DB1 are referred to and obtained by referring to the sensitivity (Δf / ΔP) and (ΔV / ΔQ) information (processing step) S11).

  In the sequential acquisition method according to the second embodiment, the first measurement stage for sensitivity estimation is executed in the processing step S12, and the second measurement stage for sensitivity estimation is executed in the processing step S13, and Δf, ΔP, ΔV, Obtain ΔQ.

  In the processing step S14, the measurement first stage and the measurement second stage are repeatedly executed a plurality of times, and when a large amount of information is obtained, the statistical method (for example, the least square method) shown in FIGS. ), Information on sensitivity (Δf / ΔP) and (ΔV / ΔQ) is obtained.

  In the next processing step S2, referring to the ancillary service information database DB3, one of the operation contents of a plurality of ancillary services is selected.

  In the processing step S3, the ancillary service is selected using sensitivity (Δf / ΔP), (ΔV / ΔQ), information on the limiting conditions, and the like under the conditions of the operation content of the ancillary service selected in the processing step S2. The value Wp of the active power P and the value Wq of the reactive power Q at the time of service operation are estimated. In estimation, information of necessary amount other than sensitivity information (Δf / ΔP), (ΔV / ΔQ) (a variation allowable range of frequency f, an upper limit value, a lower limit value, etc. with respect to the value Wp of the active power P. The value Wq of the reactive power Q) The allowable range of fluctuation of the voltage V, the upper limit value, the lower limit value, etc.) are appropriately obtained.

  In process step S4, the cable loss Lc is calculated.

  In process step S5, the control effect index E of Formula (1) is calculated. Further, in processing step S6, the processing from processing step S2 to processing step S6 is repeatedly executed until all the operation details of the ancillary service are completed.

  In process step S7, control effects are compared. The comparison is performed by selecting an operation content that maximizes the control effect index E. In addition, it is good to include the combination of power factor fixed control and the ancillary service to apply in addition to each driving | operation content of an ancillary service in the object of comparison. In the comparison of the control effects, a comparison result at a future time may be performed in addition to the comparison result at the current time point. As a result, in process step S7, the conditions are changed and executed repeatedly until all the operation details are completed. Finally, in process step S7, the active power P and the reactive power under the operation condition that maximizes the control effect index E are obtained. The output combination of Q is extracted.

  Moreover, in process step S7, the output combination of the active power P and the reactive power Q under the operating condition that maximizes the control effect index E is presented to the power transmission company as the control plan CP. The presented contents are the control plan that seems to be the most valuable in the state of the wind farm, power factor 1.0 fixed control, operation reserve power control or reactive power control that is ancillary service, and active power and reactive power Includes value maximization control. In addition, it includes specific details of the ancillary service. Further, the presented content may be current operation conditions or an operation plan at a future time.

  In processing step S8, the presence or absence of a change in the control plan CP presented to the power transmission company is confirmed. If there is no change, the initial control plan is followed. If there is a change, the change is reflected in the control plan. The wind power generation system is operated (processing step S9). In operation of the wind power generation system, it is preferable to reflect the control (4) that minimizes the cable loss.

  In short, the present invention described above maximizes profits with the intention of the power transmission company from the attitude of generating power as wind power as it is (and may be annoying from the power transmission company side). It is an invention that proposes a wind power generation system that presents and executes operation. Furthermore, in order to realize this, instead of estimating various types of profit maximization operation by receiving various data provided by the power transmission company, the profit maximization operation is estimated and calculated from the information of the power generation company's linkage points. It is.

1: wind power generation system 3: control equipment 5: power system 8: power company 31: system sensitivity analysis unit 32: control plan determination unit 311: active power value estimation unit 312: reactive power value estimation unit 313: cable loss calculation unit 100 : Wind farm GW: Wind power generator C: Power converter X: Coordination point CP: Control plan DB1 sensitivity information, necessary information database DB2: Cable characteristics, converter characteristics database DB3: Ancillary service information database

Claims (14)

A wind farm that adjusts the power supplied from the wind turbine generator to the power system via the power converter by the control device,
The control device includes: a power value estimation unit that obtains information on a value of active power or reactive power in the power system; information on the value of the active power or reactive power obtained by the power value estimation unit; and the power converter A control effect comparison unit that calculates a control effect from information on a loss from the power system to the cooperation point of the power system, and maximizes the control effect obtained by the control effect comparison unit for a plurality of operating conditions in the power system A wind farm comprising a control plan determination unit that externally presents or transmits active power or reactive power as a control plan. The wind farm according to claim 1,
The power value estimator includes information on the value of the active power or the reactive power from the sensitivity of the frequency with respect to the active power or the sensitivity of the voltage with respect to the reactive power in the power system, and information on the necessary amount of the allowable frequency or voltage. Wind farm characterized by obtaining. The wind farm according to claim 1 or 2,
A first database holding information on frequency sensitivity to reactive power or voltage sensitivity to reactive power and a necessary amount of frequency or voltage tolerance, and cooperation of the power system from the power converter A wind farm comprising a second database for holding information on loss up to a point. A wind farm according to claim 2 or claim 3,
The frequency sensitivity to the active power in the power system is obtained from the active power change and frequency change before and after the active power constant control release, and the voltage sensitivity to the reactive power in the power system is changed to the reactive power change before and after the reactive power constant control release. Wind farm, which is obtained from the voltage change. The wind farm according to claim 4,
A wind farm characterized in that the active power or reactive power is measured several times before and after the constant control release and the sensitivity of the active power or reactive power is obtained by statistical processing. The wind farm according to any one of claims 1 to 5,
The wind farm characterized in that the plurality of operating conditions include an operating condition by an ancillary service for a power system. The wind farm according to any one of claims 1 to 6,
The wind farm belongs to a power generation company, and presents a control plan for the active power or reactive power to a power transmission company that owns and manages the power system. The wind farm according to claim 7,
The wind farm is operated in accordance with the control plan of the active power or reactive power presented to the power transmission company, or is operated in accordance with a control plan modified after the presentation. The wind farm according to any one of claims 1 to 8,
The wind farm is connected to a power system linkage point from a plurality of wind power generators via a plurality of power converters, and supplies power from the plurality of wind power generators by the control device. The wind farm is characterized in that the total transmission loss of the transmission lines reaching the connection point of the power system is adjusted to the minimum. The wind farm according to claim 9, wherein
The wind farm is based on the impedance of the transmission line from the power converter to the connection point with the power system, and the distribution of reactive power is made the ratio of the reciprocal of the impedance of the transmission line, thereby A wind farm characterized by a low reactive power distribution and a high distribution of reactive power in transmission lines with low impedance. A wind farm in which a plurality of sets of outputs of a wind power generation system composed of a wind power generation device and a power converter are connected in parallel and connected to the power system at a linkage point,
A power value estimator that obtains information about the value of the active power or reactive power from the sensitivity of the frequency with respect to the active power or the voltage sensitivity with respect to the reactive power in the power system and the information on the necessary amount of the frequency or the allowable value of the voltage; The value of the value of the active power or reactive power obtained by the power value estimation unit and the information of the loss from the power converter to the cooperation point of the power system in the plurality of sets of wind power generation systems A control effect comparison unit that obtains and compares control effects with respect to a plurality of operating conditions, and a control plan decision that externally presents or transmits the active power or reactive power at the operating conditions that maximize the control effect as a control plan Wind farm characterized by having a section. A wind farm control method for adjusting power supplied from a wind power generator to a power system via a power converter by a control device,
From the sensitivity of the frequency with respect to the active power or the sensitivity of the voltage with respect to the reactive power in the power system and the information on the necessary amount of the frequency or the allowable value of the voltage , information on the value of the active power or reactive power is obtained The operation condition for maximizing the control effect by obtaining the control effect determined by the information on the value of the reactive power and the information on the loss from the power converter to the linkage point of the power system for a plurality of operation conditions A method for controlling a wind farm, characterized in that the active power or reactive power at the time of is presented externally or transmitted to a power transmission company as a control plan. A wind farm control method according to claim 12,
The wind farm is operated according to the control plan of the active power or reactive power presented to the power transmission company, or is operated according to a control plan modified after the presentation. A wind farm control method according to claim 12 or claim 13,
The wind farm is connected to a power system linkage point from a plurality of wind power generators via a plurality of power converters, and supplies power from the plurality of wind power generators by the control device. A wind farm control method, characterized in that the total transmission loss of transmission lines reaching the power system linkage point is adjusted to a minimum.

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